Precursors for ketones and aldehydes

ABSTRACT

The present invention refers to compounds of formula I  
                 
 
     as precursors for a ketone of formula II,  
                 
 
     an aldehyde or ketone of formula III, and an aldehyde or ketone of formula IV,  
                 
 
     These compounds are useful in perfumery, especially in the fine and functional perfumery.

[0001] The present invention relates to precursors for ketones andaldehydes which aldehydes and ketones are useful as fragrance materialsin fragrance compositions.

[0002] A principal strategy currently employed in imparting odors toconsumer products is the admixing of the fragrance directly into theproduct. There are, however, several drawbacks to this strategy. Thefragrance material can be too volatile and/or too soluble, resulting infragrance loss during manufacturing, storage, and use. Many fragrancematerials are also unstable over time. This again results in loss duringstorage.

[0003] In many consumer products it is desirable for the fragrance to bereleased slowly over time. Micro-encapsulation and inclusion complexeswith cyclodextrins have been used to help decrease volatility, improvestability and provide slow-release properties. However, these methodsare for a number of reasons often not successful. In addition,cyclodextrins can be too expensive for use in many applications.

[0004] It is therefore desirable to have a fragrance delivery systemwhich is capable of releasing the fragrant compound or compounds in acontrolled manner, maintaining a desired smell over a prolonged periodof time.

[0005] Precursors for the delivery of organoleptic compounds, especiallyfor flavours, fragrances and masking agents, are described in EP-A 0 936211. This delivery system releases one or more odoriferous compoundsupon exposure to light and/or UV irradiation. Using this system invarious consumer products leads to a prolonged perception of thefragrant compound(s) to be released. WO 99/60990 describes fragranceprecursors which release fragrant alcohols, aldehydes or ketones uponexposure to light.

[0006] The majority of fragrant compounds with odors accepted by thepublic are aldehydes and ketones. In fragrance compositions thesealdehydes and ketones play an important role in imparting, for example,fresh, green, floral, aldehydic and hesperidic aspects to thecomposition. In particular, aldehydes are fast degraded in alkaline andoxidative environments thereby losing their fragrant characteristic and,consequently, the desired fresh, green, floral, aldehydic and hesperidicaspects of the perfume. Therefore, they are of limited use for laundrycare products, especially detergents.

[0007] Accordingly there is a need to provide compounds which are stablein alkaline and oxidative environments, especially in laundry careproducts, and which may deposit onto treated surfaces with highsubstantivity thereby to release compounds, e.g. aldehydes and ketonesuseful as fragrance materials in fragrance compositions, upon exposureto an exogenous stimulus.

[0008] Therefor in a first aspect the present invention relates to theuse of a compound of the formula I

[0009] as a precursor for a ketone of the formula II,

[0010] an aldehyde or ketone of the formula III comprising up to 20carbon atoms,

[0011] and an aldehyde or ketone of the formula IV comprising up to 20carbon atoms,

[0012] wherein

[0013] A is an aromatic, e.g. phenyl, or a heteroaromatic ring, forexample a 5 or 6 membered heteroaromatic ring, e.g. pyridyl, pyryl,imidazilyl; or an aromatic or heteroaromatic ring as aforementionedsubstituted with one or more residues selected from the group of alkyl,aryl, aralkyl, alkenyl, alkynyl, —OH, —O-alkyl, -alkoxyalkoxy,—O-aralkyl, —O-aryl, —O-acyl, —NO₂, —NH₂, —NH-alkyl, —N(alkyl)₂,—NH-acyl, —N(acyl)₂, —CN, —SH, —S-alkyl, —S-aryl and a halogen atom,selected from fluorine, chlorine or bromine; or an aromatic orheteroaromatic ring as aformentioned bearing a residue that togetherwith the carbon atoms to which it is attached forms an aromatic oralicyclic ring, for example 5 and 6 membered rings, or an aromatic oralicyclic ring bearing one or more heteroatoms selected from oxygen,nitrogen or sulphur, which aromatic or alicyclic ring may be substitutedwith one or more residues selected from the group of alkyl, alkenyl, andalkynyl residues,

[0014] R¹ represents hydrogen, alkyl, alkenyl, alkynyl, acyl, or arylresidue, and said residues may comprise one or more oxygen atom(s),

[0015] R², R³, R⁴, R⁵ represent independently hydrogen, alkyl, alkenyl,alkynyl, cycloalkyl, cycloalkenyl or aromatic residues, and saidresidues may comprise one or more oxygen atoms, or

[0016] R² and R³ together with the carbon atom to which they areattached may form a 4 to 18 membered carbocyclic ring, optionallysubstituted by an alkyl, alkenyl or alkynyl residue having up to 10carbon atoms, and the ring and residues may comprise one or more oxygenatoms,

[0017] R⁴ and R⁵ together with the carbon atom to which they areattached may form a 4 to 18 membered carbocyclic ring, optionallysubstituted by an alkyl, alkenyl or alkynyl residue having up to 10carbon atoms, and the ring and residues may comprise one or more oxygenatoms, and

[0018] n is an integer from 1 to 3.

[0019] As used in relation to compounds of formula I unless otherwiseindicated “alkyl” refers to C₁-C₂₀, preferably C₁-C₄,e.g. methyl, ethyl,isobutyl, or C₅-C₁₈, e.g. hexyl, (2-ethylhexyl)-; “aryl” refers toC₆-C₂₀, preferably C₆-C₁₀,e.g. phenyl, naphthyl, or C₁₁-C₁₅, e.g.anthryl; “aralkyl” refers to C₇-C₂₀, preferably C₇-C₁₅, e.g. benzyl,phenylethyl, phenylpropyl; “alkenyl” refers to C₂-C₂₀, e.g. vinyl,vinylpropenyl, isobutenyl, preferably C₅-C₁₇, e.g. 9-decenyl,10-undecenyl, 3,7-dimethyl-6-octenyl; “alkynyl” refers to C₂-C₂₀,preferably C₂-C₁₀, e.g. ethynyl, propynyl, heptynyl, octynyl,6-methyl-heptynyl; “acyl” refers to C₁-C₂₀, preferably C₂-C₁₀, e.g.acetyl, benzoyl, or C₁₁-C₁₈, e.g. dodecanoyl, hexadecanoyl; “cycloalkyl”refers to C₃-C₂₀, preferably C₄-C₈, e.g. cyclobutyl, cycloheptyl,3,3-dimethyl-cyclohexyl, or C₉-C₁₈, e.g. cyclodecanyl; “cycloalkenyl”refers to C₃-C₂₀, preferably C₄-C₈, e.g. cyclopentadienyl,cyclooctatetraenyl, 2,2,3-trimethyl-3-cyclopentenyl, cyclooctenyl orC₉-C₁₈, e.g. cyclododecenyl, 2,4,5-trimethyl-3-cyclohexenyl,cyclopentadecenyl; and “alkoxyalkoxy” refers to C₃-C₂₀, preferablyC₃-C₁₀, e.g. methoxyethoxy, methoxy-(ethoxy)₂, methoxypropoxy orC₁₁-C₁₈, e.g. methoxy-(ethoxy)₅.

[0020] The compounds of formula I release upon exposure to lightvolatile aldehydes and ketones of formula III and IV and ketones offormula II. Since the compounds of formula I are stable in alkaline andoxidative environment and show high substantivity, they are excellentlyadapted for use in detergent and laundry care products.

[0021] The compounds of formula I are slowly cleaved when exposed tolight, in particular daylight. Upon absorption of energy from saidlight, the compounds of formula I undergo twice a Norrish Type IIphotoreaction which leads to the release of a ketone of formula II andan aldehyde and/or ketone of formula III and IV.

[0022] The compounds of formula I cleaved particularly well in lighthaving a wavelength range of 200 nm to 800 nm, although irradiation withlight having a wavelength from about 250 nm to 400 nm is preferred.

[0023] The release of the above mentioned compounds occurs for exampleupon exposure to sunlight penetrating through ordinary windows and beingnot particularly rich in UV irradiation. It is needless to say that uponexposure to bright sunlight, in particular outdoors, the release of thecompounds of formula II, III and IV will occur faster and to a greaterextent than upon exposure to room light of natural or artificial origininside a building. The cleavage of the compounds of formula I can alsobe initiated by an appropriate lamp, for example a sun-tanning lamp.

[0024] The photoreaction of the compounds of formula I involves, in afirst step, the absorption of light by the keto-group followed byabstraction of the acetal-H atom and subsequent cleavage of theresulting 1,4-di-radical (Scheme A). It has been found that the residueA of the compounds of formula I plays an important role in thisphotoreaction as it influences the absorption maximum λ_(max) of theketo-group. Therefore, the cleavage properties of the compounds offormula I can be modified by variation of A.

[0025] The ketone of formula II can be a ketone with fragrant propertiesand/or can have the function to stabilize the chemical structure, and/orcan be a substantivity and/or light-absorbance-enhancing element of acompound of formula I.

[0026] A ketone of formula II having fragrant properties is a compoundknown to a person skilled in the art as being a useful ingredient forthe formulation of perfumes or perfumed articles. Non-limiting examplesof said ketones are:

[0027] 1-(4-methoxyphenyl)-ethanone (acetanisole)*,

[0028] 1-phenyl-ethanone (acetophenone),

[0029] 1-(6-tert-butyl-1,1-dimethyl-indan-4-yl)-ethanone*,

[0030] 1-(2,4-dimethylphenyl)-ethanone (dimethyl acetophenone)*,

[0031]1-(3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanone**,

[0032] 1-(5,6,7,8-tetrahydro-2-naphthalenyl)-ethanone*,

[0033] 3-methyl-1-(4-methylphenyl)-4-hexen-1-one,

[0034] 1-phenyl-4-penten-1-one,

[0035] 1-(1,1,2,3,3-pentamethyl-indan-5-yl)-ethanone*,

[0036] 1-(2-naphthalenyl)-ethanone*,

[0037] 1-(1,1,2,3,3,6-hexamethyl-indan-5-yl)-ethanone*,

[0038] 1-phenyl-propan-2-one (propiophenone),

[0039] 1-[1,1,2,6-tetra-methyl-3-(1-methylethyl)-indan-5-yl]-ethanone**,

[0040]1-(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanone*,

[0041]1-(3-ethyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanone*,

[0042] whereby * indicates the preferred ketones and ** indicate themore preferred ketones.

[0043] It is obvious to the person skilled in the art that the abovelist is illustrative and that the present invention relates to manyother ketones of formula II, more particular ketones having fragrantproperties.

[0044] Aldehydes of formula III and IV represent an important class ofperfumery raw materials and comprise compounds of a vast structuralvariety. Aldehydes of formula III and IV contribute to the odor andaroma of various flowers and fruits and are known to be usefulingredients for the formulation of perfumes or perfumed articles. In thefollowing list non-limiting examples of such aldehydes are given:

[0045] 2,6,10-trimethylundec-9-enal*,

[0046]8,8-dimethyl-1,2,3,4,5,6,7,8-octahydro-naphthalene-2-carbaldehyde,

[0047] (4-isopropyl-phenyl)-ethanal,

[0048] 2,4-dimethyl-cyclohex-3-ene-1-carbaldehyde*,

[0049] 1,3,5-trimethyl-cyclohex-1-ene-4-carbaldehyde*,

[0050] 4-(4-hydroxy-4-methylpentyl)-cyclohex-3-ene-1-carbaldehyde*,

[0051] hex-2-enal*,

[0052] 3,5,5-trimethyl-hexanal,

[0053] heptanal*,

[0054] 2,6-dimethyl-hept-5-enal*,

[0055] decanal**,

[0056] dec-9-enal,

[0057] dec-4-en-1-al,

[0058] 2-methyl-decanal*,

[0059] undec-10-en-1-al**,

[0060] undecanal*,

[0061] dodecanal**,

[0062] 2-methyl-undecanal**,

[0063] tridecanal,

[0064] tridec-2-enal,

[0065] octanal**,

[0066] nonanal*,

[0067] non-2-enal,

[0068] undec-9-enal**,

[0069] 2-phenyl-propanal*,

[0070] 2-(4-methyl-phenyl)-ethanal*,

[0071] 3,7-dimethyl-octanal*,

[0072] dihydrofarnesal**,

[0073] 7-hydroxy-3,7-dimethyl-octanal*,

[0074] 2,6-dimethyl-oct-5-en-1-al,

[0075] 3-(3-isopropyl-phenyl)-butanal**,

[0076] 2-(3,7-dimethyl-oct-6-en-oxy)-ethanal,

[0077] 4-(4-methyl-pent-3-enyl)-cyclohex-3-ene-1-carbaldehyde*,

[0078] 2,3,5,5,-tetramethyl-hexanal,

[0079] longifolic aldehyde,

[0080] 2-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)-butanal*,

[0081] 2-methyl-3-(4-tert-butylphenyl)-propanal**,

[0082] 3-(4-tert-butyl-phenyl)-propanal*,

[0083] 2-(4-isopropyl-phenyl)-propanal,

[0084] 3-(benzo[1,3]dioxol-5-yl)-2-methyl-propanal*,

[0085] 3,7-dimethyl-oct-6-ene-1-al*,

[0086] 2-methyl-3-(4-isopropylphenyl)-propanal*,

[0087] 4-tert-butyl-cyclohexane-1-carbaldehyde,

[0088] 4-(octahydro-4,7-methano-5H-inden-5-ylidene)-butanal,

[0089] (3,7-dimethyl-oct-6-enyloxy)-ethanal**,

[0090] (2E,6Z)-nonadienal*,

[0091] 2,4-dimethyl-2,6-heptadienal,

[0092] (E)-dec-2-enal*,

[0093] dodec-2-enal*,

[0094] 3,7-dimethyl-octa-2,6-dienal*,

[0095] 2,4-diethyl-hepta-2,6-dienal,

[0096] 3,7-dimethyl-nona-2,6-dienal*,

[0097] 3-propyl-hept-2-enal,

[0098] 4-isopropenyl-cyclohex-1-ene-1-carbaldehyde,

[0099] whereby * indicates the preferred aldehydes and ** indicate themore preferred aldehydes.

[0100] Ketones of formula III and IV represent another important classof perfumery raw materials and comprise compounds of a vast structuralvariety. Ketones of formula III and IV contribute to the odor and aromaof various flowers and fruits and are known to be useful ingredients forthe formulation of perfumes or perfumed articles. In the following listnon-limiting examples of such ketones are given:

[0101] 2,5-dimethyl-oct-2-en-6-one**,

[0102] 4-(2,6,6-trimethylcyclohex-1-en-1-yl)-butan-2-one*,

[0103] 4-(2,6,6-trimethylcyclohex-2-en-1-yl)-butan-2-one*,

[0104] 4-(2,5,6,6-tetramethyl-2-cyclohexen-1-yl)-but-3-en-2-one*,

[0105] 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-methyl-but-3-en-2-one*,

[0106] 5-isopropenyl-2-methyl-cyclohex-2-enone*,

[0107] 1-(4-hydroxyphenyl)-butan-3-one**,

[0108] 4-(1,3-benzodioxole-5-yl)-butan-2-one**,

[0109] 2-heptyl-cyclopentanone**,

[0110] nonan-2-one**,

[0111] octan-2-one**,

[0112] heptan-2-one**,

[0113] undecan-2-one**,

[0114] 4-phenyl-butan-2-one**,

[0115] 6-methyl-hept-5-en-2-one**,

[0116] 2-(sec-butyl)-cyclohexanone**,

[0117] 2-hexyl-cyclopent-2-en-1-one**,

[0118] 2-(isopropyl)-5-methyl-cyclohexanone*,

[0119] 5-methyl-2-propyl-cyclohexanone**,

[0120] 4-(1,1-dimethylpropyl)-cyclohexanone**,

[0121] 6,10-dimethyl-undeca-5,9-dien-2-one**,

[0122] (3-oxo-2-pentyl-cyclopentyl)-acetic acid methyl ester**,

[0123] 3-(2-Oxo-propyl)-2-pentyl-cyclopentanone**,

[0124]cis-1-(1,2,3,4,5,6,7,8-octahydro-1,2,8,8-tetramethyl-2-naphthalenyl)-ethanone*,

[0125]1-(2,3,8,8-tetramethyl-1,2,3,4,5,6,7,8-octahydro-naphthalen-2-yl)-ethanone*,

[0126] 1-cyclohex-2-enyl-2,4-dimethyl-pent-2-en-1-one*,

[0127] 2-hexyl-cyclopent-2-en-1-one*,

[0128] 2-pentyl-cyclopent-2-enone,

[0129] 3-methyl-2-pentyl-cyclopent-2-enone*,

[0130] 2-hexylidene-cyclopentanone*,

[0131] 3,5-diethyl-5,6-dimethyl-cyclohex-2-enone*,

[0132]6-isopropenyl-4,4a-dimethyl-4,4a,5,6,7,8-hexahydro-3H-naphthalen-2-one*,

[0133] 3-methyl-6-propylidenecyclohexanone*,

[0134] 4-(1-methylethyl)-cyclohex-2-en-1-one,

[0135] (E)-oct-3-en-2-one,

[0136]1-(3,6,8,8-tetramethyl-2,3,4,7,8,8a-hexahydro-1H-3a,7-methano-azulen-5-yl)-ethanone*,

[0137] 1-(3,3-dimethyl-cyclohex-1-enyl)-ethanone*,

[0138] 1-(2,4,6-trimethylcyclohex-3-en-1-yl)-but-1-en-3-one,

[0139] 2-(3-methylbut-2-en-1-yl)-3-methyl-cyclopent-2-en-1-one,

[0140]3-methyl-5-(2,2,3-trimethyl-cyclopent-3-en-1-yl)-pent-3-en-2-one*,

[0141] 5-butylidene-2,2,4-trimethylcyclopentanone,

[0142] 1,1,2,3,3-pentamethyl-1,2,3,5,6,7-hexahydro-inden-4-one*,

[0143] 3-methyl-5-propyl-cyclohex-2-en-1-one*,

[0144] 6-isopropyl-4,4a,5,6,7,8-hexahydro-3H-naphthalen-2-one,

[0145] 3,5,5-trimethyl-cyclohex-2-en-1,4-dione*,

[0146] (E)-5-methyl-2-hepten-4-one,

[0147] acetyl diisoamylene*,

[0148] dec-3-en-2-one,

[0149] 4-(2-ethyl-3,6,6-trimethyl-cyclohex-2-enyl)-but-2-enal,

[0150] 1-(5,5-dimethyl-1(6)-cyclohexen-1-yl)-4-penten-1-one*,

[0151] 1-(2,6,6-trimethyl-1-cyclohexen-1-yl)-but-2-en-1-one*,

[0152] 1-(2,6,6-trimethyl-2-cyclohexen-1-yl)-but-2-en-1-one*,

[0153] 1-(2,6,6-trimethyl-3-cyclohexen-1-yl)-but-2-en-1-one*,

[0154] 4-(2,5,6,6-tetramethyl-2-cyclohexen-1-yl)-but-3-en-2-one*,

[0155] 2,4,4,5,5-pentamethyl-1-cyclopentene-1-yl-ethanone*,

[0156] cyclohexadec-5-enone**,

[0157] cyclopentadecanone**,

[0158] 3-methyl-cyclopentadecanone**,

[0159] 7-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-one**,

[0160] whereby * indicates the preferred ketones and ** indicate themore preferred ketones.

[0161] Additional aldehydes and ketones of formula II, III and IV havingfragrant properties are e.g. described in “Perfume and FlavorChemicals”, S. Arctander Ed., Vol. I & II, Allured PublishingCorporation, Carol Stream, USA, 1994; and in “Common Fragrance andFlavor Materials”, K. Bauer, D. Garbe and H. Surburg, Eds., Wiley-VCH,3d Edition, Weinheim, 1997.

[0162] Many of the aldehydes and ketones of formula III and IV describedabove, which are of pleasant odor, are rather volatile, and/or unstablein aggressive media, and/or considerably water soluble.

[0163] The compounds of formula I are not, or only slightly, volatile.The ketones of formula II and the aldehydes and ketones of formula IIIand IV are released only upon exposure to light, and especiallydaylight. The photochemical cleavage provides, over days and weeks,perceptible amounts of aldehydes and ketones. The period depends interalia on the amount or concentration of the compounds of formula Iapplied, the duration of exposure to light, its intensity and itswavelength.

[0164] Aldehydes and ketones of formula III and IV are prone todegradation, especially in alkaline and bleaching (oxidising) productssuch as detergents. They are also considerably water soluble and to someextent are washed away in washing/cleaning processes. These facts mayresult in considerable loss of perfume and in particular the notesimparted paricularly by aldehydes.

[0165] Today's consumers select a certain product not only based onfunctional performance but also based on the odor. From the foregoing itis evident that systems for introducing a variety of fragrance accordsto products having alkaline pH and bleaching acivity are desirable. Thecompounds of formula I have the advantage that they are not, or onlyslightly, volatile and chemically stable in consumer products havingalkaline and/or neutral pH and/or bleaching activity. A compound offormula I added to a powder detergent, is stable in the detergent powderthroughout storage. During the washing cycle (alkaline pH) and therinsing cycle (neutral pH) the compound is deposited on the fabricsurface. It is only upon exposure of the fabric to light, for exampleduring line-drying in the sun, that the release of the ketone of formulaII and the aldehydes and ketones of formula III and IV is started.

[0166] It has been mentioned above that aldehydes and ketones of formulaIII and IV are rather volatile compounds. This is especially true forlow molecular weight aldehydes and ketones being substituted byaliphatic chains, for example aldehydes and ketones having a molecularweight less than 200. Furthermore, they are to a certain extent watersoluble and are, therefore, lost to some extent during thewashing/rinsing cycle if introduced directly. The compounds of formula Ihave the advantage that they have good substantivity on differentsubstrates, especially on fabrics. Furthermore, the compounds of formulaI are not, or only slightly, volatile thus no loss occurs duringstorage. By means of the compounds of formula I highly volatilealdehydes and ketones of formula III and IV with low substantivity maybe successfully applied to achieve a long lasting pleasant odor. Thevolatile aldehydes and ketones are produced in situ after application ofthe compound of formula I onto a fabric during the washing cycle uponactivation by light.

[0167] In the compounds of formula I the moiety derived from a ketone offormula II brings three advantages: it introduces stability as well assubstantivity to the compounds and upon activation by light it canexhibit fragrant properties.

[0168] The compounds of formula I are advantageously prepared via thefollowing methods. Firstly, when R¹ is H, the ketone of formula II isoxidised with concentrated aqueous hydrobromic acid in dimethylsulfoxide (H. Brawner Floyd et al., J. Org. Chem., 1985, 50, 5022-5027)to give the hydrated arylglyoxal. This is converted into thecorresponding diethyl acetal under mildly acid conditions.Alternatively, the corresponding dimethyl acetal can be accesseddirectly by the treatment of the ketone of formula II withdiphenyldiselenide and ammonium peroxydisulfate in methanol (M. Tieccoet al., J. Org.

[0169] Chem., 1990, 55, 4523-4528). Trans-acetalisation with the alcoholderived from aldehydes or ketones of formula III and IV under mildlyacidic conditions yields the compound of formula I. These syntheses areillustrated in scheme I:

[0170] According to a further method the ketone of formula II ishalogenated with for example sulfuryl halide in dimethylformamide. If Ain formula II contain nitrogen substituents such as amines, thebromination in concentrated sulfuric acid can be employed (Z. Diwu etal., Tetrahedron Lett., 1998, 39, 4987-4990). The intermediate dihalidecan be substituted with sodium methylate or potassium carbonate inmethanol. Mildly acidic trans-acetalisation with the alcohol derivedfrom aldehydes and ketones of the formula III and IV then affords thecompounds of formula I. The syntheses via this route is illustrated inscheme II:

[0171] Preferred compounds of the formula I are compounds releasingaldehydes of the formula III and IV, wherein n=1, R² and R⁴ areindependently an alkyl, alkenyl, alkynyl residue having 5 to 17 carbonatoms, and R³ and R⁵ are H. Most preferred compounds are those releasingfatty aldehydes having 6 to 13 carbon atoms and 2-methyl-undecanal.

[0172] Other preferred compounds of formula I include compounds whereinn=1, R² and R⁴ are independently the residue of a cyclic or acyclicterpene or of a terpenoic aldehyde, i.e. a terpene derived aldehyde,e.g. an aldehyde obtained in one or more synthetic steps fromterpenoids, having 4 to 15 carbon atoms, and R³ and R⁵ are H. Mostpreferred compounds are those releasing citronellal, citral,7-hydroxydihydrocitronellal, 7-methoxydihydro-citronellal and2,6,10-trimethyl-9-undecenal [ADOXAL¹⁾].

[0173] Other preferred compounds of formula I include compounds whereinn=1, R² and R⁴ are cycloaliphatic residues having 4 to 15 carbon atoms,and R³ and R⁵ are H. Most preferred compounds are those releasing2,4-dimethyl-3-cyclohexene carboxaldehyde [CYCLAL C¹)],4-(4-methyl-3-penten-1-yl)-3-cyclohexene carboxaldehyde [MYRALDEN¹⁾],and 4-(4-hydroxy-4-methylpentyl)-3-cyclohexene carboxaldehyde [LYRAL³)].

[0174] Other preferred compounds are those wherein n=1, R² and R⁴ areindependently a substituted or unsubstituted aromatic residue having 4to 15 carbon atoms, and R³ and R⁵ are H. Most preferred compounds arethose releasing benzaldehyde, 4-methoxybenzaldehyde (p-anisaldehyde),3,4-methylenedioxybenzaldehyde (heliotropine, piperonal),phenylacetaldehyde, 3-phenylpropanal, 2-phenylpropanal,4-methylphenylacetaldehyde, 3-(4-ethylphenyl)-2,2-dimethylpropanal[FLORALOZONE³⁾], 2-methyl-3-(4-isopropylphenyl)-propanal(Cyclamenaldehyde), 2-methyl-3-(4-tert-butylphenyl)-propanal [LILIAL¹⁾],cinnamaldehyde, 2-pentyl-3-phenyl-2-propenal (α-amyl-cinnamaldehyde),2-hexyl-3-phenyl-2-propenal (α-hexyl-cinnamaldehyde),4-hydroxy-3-methoxybenzaldehyde (vanillin) and3-ethoxy-4-hydroxybenzaldehyde (ethylvanillin).

[0175] Other preferred compounds are those wherein n=1, R² and R³ arealkyl, alkenyl or alkynyl residues having together 5 to 17 carbon atoms,and R⁴ and R⁵ are alkyl, alkenyl or alkynyl residues having together 5to 17 carbon atoms. A most preferred compound is one that releases3-octanone.

[0176] Other preferred compounds of formula I include compounds whereinn=1 and R², R³, R⁴ and R⁵ are the residues of cyclic or acyclic terpeneor terpenoic ketones, i.e. terpene derived ketones, e.g. a ketoneobtained in one or more synthetic steps from terpenoids, having 4 to 15carbon atoms. Most preferred compounds are those releasing6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), (menthones andisomenthones), 1,8-p-menthadien-6-one (carvone),1,7,7-trimethylbicyclo[2.2.1]heptan-2-one (camphor),1,3,3-trimethylbicyclo[2.2.1]heptan-2-one (fenchone),4-(2,6,6-trimethylcyclohexenyl)-3-butene-2-ones and4-(2,6,6-trimethylcyclohexenyl)-butan-2-ones (ionones anddihydroionones), 1-(2,6,6-trimethylcyclohexenyl)-2-butene-1-ones(damascones), 5,6-dimethyl-8-isopropenylbicyclo[4.4.0]-dec-1-en-3-one(nootkatone) and cedryl methyl ketone.

[0177] Other preferred compounds are those wherein n=1, and R², R³, R⁴,and R⁵ are the residues of cycloaliphatic ketones having 8 to 18 carbonatoms. Most preferred compounds are those releasing2-pentylcyclopentanone [DELPHONE²)], 2-heptylcyclopentanone [ALISMONE(Haarmann & Reimer GmbH, Germany)],2,2,5-trimethyl-5-pentylcyclopentanone [VELUTONE²⁾],3-methyl-2-pentyl-2-cyclopenten-1-one (dihydrojasmone),3-methyl-2-(2-cis-penten-1-yl)-2-cyclopenten-1-one (cis-jasmone),4-tert-pentylcyclohexanone [ORIVONE³⁾],6,7-dihydro-1,1,2,3,3-pentamethyl-4(5H)-indanone [CASHMERAN³⁾],cyclopentadecanone [EXALTONE²⁾], 3-methylcyclopentadecanone[MUSCENONE²⁾], 5-cyclohexadecen-1-one, 9-cycloheptadecen-1-one[CIVETTONE²⁾], 5-cyclohexadecen-1-one [VELVIONE],1-(5,5-dimethyl-1-cyclohexen-1-yl)-4-penten-1-one [DYNACONE²⁾] and1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthalenyl)-ethanone[ISO E SUPER³⁾] whereby ¹⁾ indicates Givaudan SA, Vernier, Switzerland,²⁾ indicates Firmenich SA, Switzerland, and ³⁾ indicates InternationalFlavors & Fragrances, USA as supplier.

[0178] Other preferred compounds are those wherein n=1, R², R³, R⁴, andR⁵ are the residues of araliphatic ketones having 8 to 18 carbon atoms.Most preferred compounds are those releasing4-(4-hydroxyphenyl)-2-butanone (raspberry ketone) and4-phenyl-2-butanone (benzylacetone).

[0179] Other preferred compounds of formula I include compounds whereinn=1 and R¹=H. Most preferred are compounds which upon cleavage of thesecompounds release a ketone of formula II wherein said ketone is an arylmethyl ketone.

[0180] Other preferred compounds are those wherein n=1 and R¹ representsan alkyl, alkenyl, aralkyl or aryl residue having 1 to 20 carbon atoms.Most preferred are compounds which upon cleavage of these compoundsrelease propiophenone.

[0181] Other preferred compounds of formula I are compounds wherein n=1,R¹=H, and A is an aromatic ring, e.g. phenyl; or an aromatic ringsubstituted with one or more residues selected from the group of alkyl,alkenyl, alkynyl, and alkoxy; or an aromatic ring, e.g. phenyl, bearinga residue that together with the carbon atoms to which it is attachedforms an aromatic or alicyclic ring, for example 5 and 6 membered rings,or an aromatic or alicyclic ring bearing one or more heteroatomsselected from oxygen, nitrogen or sulphur, which aromatic or alicyclicring may be substituted with one or more residues selected from thegroup of alkyl, alkenyl, and alkynyl residues. Most preferred compoundsare those releasing a ketone of formula II selected from1-phenyl-ethanone (acetophenone), 1-(4-methoxyphenyl)-ethanone(acetanisole), 2,4-dimethylphenyl-ethanone,1-(4-methoxyphenyl)-ethanone, 1-(2-naphtalenyl)-ethanone,4-acetyl-6-tert-butyl-1,1-dimethyl-indan,1-(5,6,7,8-tetrahydro-3′,5′,5′,6′,8′,8′-hexamethyl-2-naphthalenyl)-ethanone,1-(5,6,7,8-tetrahydro-3′,5′,5′,8′,8′-pentamethyl-2-naphthalenyl)-ethanone,1-(5,6,7,8-tetrahydro-3′-ethyl-5′,5′,8′,8′-tetramethyl-2-naphthalenyl)-ethanone,1-(2,3-dihydro-1′,1′,2′,3′,3′,6′-hexamethyl-1H-inden-5-yl)-ethanone,1-[2,3-dihydro-1′,1′,2′,6′-tetramethyl-3-(1-methylethyl)-1H-inden-5-yl]-ethanone,5-acetyl-1,1,2,3,3-pentamethyl-indane, and1-(5,6,7,8-tetrahydro-2-naphthalenyl)-ethanone.

[0182] Other preferred compounds are those wherein n=1, R¹=H and A is aheteroaromatic ring, for example a 5 or 6 membered heteroaromatic ring,e.g. pyridyl, pyryl, imidazilyl; or an aromatic, e.g. phenyl orheteroaromatic ring, e.g. pyridyl, pyryl, imidazilyl, substituted withone or more residues selected from the group —OH, —O-alkyl,-alkoxyalkoxy, —O-aralkyl, —O-aryl, —O-acyl, —NO₂, —NH₂, —NH-alkyl,—N(alkyl)₂, —NH-acyl, —N(acyl)₂, —SH, —S-alkyl, —S-aryl; or an aromaticor heteroaromatic ring as aformentioned bearing a residue that togetherwith the carbon atoms to which it is attached forms an aromatic oralicyclic ring, for example 5 and 6 membered rings, or an aromatic oralicyclic ring bearing one or more heteroatoms selected from oxygen,nitrogen or sulphur, which aromatic or alicyclic ring may be substitutedwith one or more residues selected from the group of alkyl, alkenyl, andalkynyl residues. Most preferred compounds are those releasing a ketoneof formula II selected from 4-alkoxy-acetophenones,4-alkylthioacetophenones, 4-dialkylamino-acetophenones,4-acylamino-acetophenones, 4-diacylamino-acetophenones,31,41-(methylenedioxy)-acetophenone, 2,4-dialkoxy-acetophenones,4-(2-methoxyethoxy)-acetophenone, 2,4-di-(2-methoxyethoxy)-acetophenone,4-[2-(2-methoxyethoxy)-ethoxy]-acetophenone,2,4-di-[2-(2-methoxyethoxy)-ethoxy]-acetophenone,1-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-ethanone.

[0183] Other preferred compounds of formula I are those, wherein thereleased compounds of formula III and IV are the same.

[0184] Those compounds of the formula I are especially preferred,wherein n is 1, R¹ is H, methyl, phenyl,

[0185] A is phenyl, 6-tert-butyl-1,1-dimethyl-indan-4-yl,2,4-dimethylphenyl,3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,5,6,7,8-tetrahydro-2-naphthalenyl, 1,1,2,3,3-pentamethyl-indan-5-yl,2-naphthalenyl, 1,1,2,3,3,6-hexamethyl-indan-5-yl,1,1,2,6-tetra-methyl-3-(1-methylethyl)-indan-5-yl,3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,3-ethyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,4-alkoxy-phenyl, 4-dialkylamino-phenyl, 4-acylamino-phenyl,4-diacylamino-phenyl, 3,4-(methylenedioxy)-phenyl, 3,4-dialkoxy-phenyl,4-(2-methoxyethoxy)-phenyl, 3,4-di-(2-methoxyethoxy)-phenyl,4-[2-(2-methoxyethoxy)-ethoxy]-phenyl,3,4-di-[2-(2-methoxyethoxy)-ethoxy]-phenyl,2,3-dihydro-benzo[1,4]dioxin-6-yl, and

[0186] R²═R⁴ are H, and R³═R⁵ are 6,10-dimethylundec-9-ene-2-yl,2,4-dimethyl-cyclohex-3-ene-1-yl, 1,3,5-trimethyl-cyclohex-1-ene-4-yl,4-(4-hydroxy-4-methyl-pentyl)-cyclohex-3-ene-1-yl, pent-1-enyl, hexyl,6-methyl-hept-5-ene-2-yl, nonyl, 2-decyl, 9-decenyl, decyl, undecyl,2-undecyl, heptyl, octyl, 8-decenyl, 1-phenyl-ethyl,(4-methyl-phenyl)-methyl, 2,6-dimethyl-heptyl,2,6,10-trimethyl-undeca-5,9-dienyl, 2,6-dimethyl-6-hydroxy-heptyl,2-(3-isopropyl-phenyl)-propyl,4-(4-methyl-pent-3-enyl)-cyclohex-3-ene-1-yl,4-(2,6,6-trimethylcyclohex-2-en-1-yl)-2-butyl,3-(4-tert-butylphenyl)-2-propyl, 2-(4-tert-butylphenyl)-ethyl,3-(benzo[1,3]dioxol-5-yl)-2-propyl, 2,6-dimethyl-5-heptenyl,3-(p-isopropyl-phenyl)-2-propyl, (3,7-dimethyl-oct6-enyloxy)-methyl,(5Z)-octa-1,5-dienyl, 1-nonenyl, 1-undecenyl,2,6-dimethyl-hepta-1,5-dienyl, 2,6-dimethyl-octa-1,5-dienyl, or

[0187] R²═R⁴ are methyl, and R³═R⁵ are pentyl, hexyl, heptyl, octyl,nonyl, 2-phenyl-ethyl, 4-methyl-pent-3-ene-1-yl,4,8-dimethyl-nona-3,7-dien-1-yl,(2,6,6-trimethylcyclohex-1-ene-1-yl)-ethyl,(2,6,6-trimethylcyclohex-1-ene-2-yl)-ethyl, 2-(4-hydroxyphenyl)-ethyl,(1,3-benzodioxole-5-yl)-ethyl, or

[0188] R²═R⁴ are ethyl, and R³═R⁵ are 5-methyl-hex-4-en-2-yl, or

[0189] R²CHR³═R⁴CHR⁵ are 2-heptyl-cyclopentyl,7-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-yl,3-methyl-cyclopentadecyl, cyclopentadecyl, 5-cyclohexadecen-1-yl,4-(1,1-dimethylpropyl)-cyclohexyl,2-(2-methylethyl)-5-methyl-cyclohexyl,2-(1-methylethyl)-5-methyl-cyclohexyl, 2-(butan-2-yl)-cyclohexyl,3-(2-oxo-propyl)-2-pentyl-cyclopentyl,2-pentyl-3-(methoxycarbonylmethyl)-cyclopentyl, and these compoundsconstitute another aspect of the present invention.

[0190] Since the compounds of formula I, upon exposure to light arecleaved and provide a ketone of formula II and aldehydes or ketones offormula III and IV, they permit the development of useful consumerproducts with enhanced fragrant properties, especially having longlasting pleasant odor. Therefore, the present invention also relates tothe use of all compounds of formula I as precursors for fragrantcompounds.

[0191] The compounds of formula I can be used in any product in which aprolonged and defined release of the above mentioned fragrant compoundsis desired. Therefore, these compounds are especially useful infunctional perfumery, in products which are exposed to (sun)light duringor after application.

[0192] The compounds of formula I can act as fragrance precursors infunctional and fine perfumery i.e. in fine fragrances, industrial,institutional, home and personal care products. Industrial,institutional and home cleaning products to which the compound offormula I can be added are all kinds of detergents, window cleaners,hard surface cleaners, all purpose cleaners and furniture polishes. Theproducts can be liquids or solids, such as powders or tablets. Fabricsand surfaces treated with a product comprising a compound of formula Iwill diffuse a fresh and/or clean odor upon exposure to light muchlonger than when cleaned with a conventional cleaner. Fabrics or clotheswashed with such detergents will release the aldehydes and ketones evenafter having been stored for weeks in a dark place, e.g. a wardrobe.

[0193] The compounds of the formula I are also useful for application inall kinds of body care products. Especially interesting products arehair care products, for example shampoos, conditioners and hairspraysand skin care products such as cosmetic products and especially sunprotection products.

[0194] The above mentioned examples are of course only illustrative andnon-limiting. Many other products to which the compound of formula I maybe added include soaps, bath and shower gels, deodorants and evenperfumes and colognes.

[0195] The compounds of formula I can be used alone or in combinationwith other fragrance ingredients, solvents or adjuvants known to thoseskilled in the art. Such ingredients are described, for example, in“Perfume and Flavor Chemicals”, S. Arctander, Ed., Vol. I & II, AlluredPublishing Corporation, Carol Stream, USA, 1994 and include fragrancecompounds of natural or synthetic origin and essential oils.

[0196] The amounts in which the compounds of formula I are incorporatedin the various above-mentioned products vary within a wide range. Theamounts depend on the nature of the aldehydes and ketones to bereleased, the nature of the product to which the compounds of formula Iare added and the desired olfactory effect. The amounts used also dependon the co-ingredients in a given composition when the compounds offormula I are used in admixture with perfuming co-ingredients, solventsor adjuvants. Typical concentrations are in the order of 0.01% to 5% byweight of the products.

[0197] The following non-limiting examples further illustrate theembodiments of the invention.

[0198] The following chemicals were obtained from commercial sources:2,2-dimethoxy-2-phenylacetophenone, α,α-diethoxy-acetophenone,2′-acetonaphthone, acetanisole, 4′-hydroxyacetophenone,4′-(methylthio)-acetophenone, 3′,4′-(methylendioxy)-acetophenone,3′,4′-dimethoxy-acetophenone, Fixolide®, 4′-(diethylamino)-acetophenone,10-undecene-1-ol, 1-hexanol, β-citronellol, (−)-menthol.

[0199] The following alkohols are known in the literature and wereprepared from their corresponding commercially available aldehyde orketone by standard lithium alimunium hydride reduction:2,6,10-trimethyl-undec-9-en-1-ol, 2,6-dimethyl-hept-5-en-1-ol,2-methyl-undecan-1-ol, 3-(4-tert-butyl-phenyl)-2-methyl-propan-1-ol,3-(3-isopropyl-phenyl)-butan-1-ol,(2,4-dimethyl-cyclohex-3-enyl)-methanol,4-(2,6,6-trimethyl-cyclohex-1-enyl)-butan-2-ol.

[0200] NMR: values of coupling constants J are given in Hertz.

EXAMPLE 1

[0201] Preparation of Aroyl Formaldehyde Acetals

[0202] 1. General Procedure for the Preparation of para-O-substitutedAcetophenones

[0203] To a mechanically stirred mixture of 4′-hydroxyacetophenone (27.3g, 0.2 mol), anhydrous potassium carbonate (33.2 g, 0.24 mol, 1.2equiv.) and potassium iodide (3.2 g, 0.02 mol, 0.1 equiv.) indimethylformamide (250 ml) was added dropwise the corresponding alkylchloride or bromide (0.24 mol, 1.2 equiv.). Then, the mixture was heatedat either 60° C. (for alkyl bromides) or 80° C. (for alkyl chlorides)for 6-16 h. The completion of the reaction was monitored by TLC or GLC.The off-white to beige reaction mixture was poured into ice/water (300ml) and extracted with MTBE (2×250 ml). The organic phases were eachwashed with water (200 ml) and brine (100 ml), combined, dried (Na₂SO₄)and concentrated in vacuo to give the required product in usuallyquantitative yield.

[0204] 1-(4-Propoxy-phenyl)-ethanone

[0205] Obtained as a very pale yellow oil according to the generalprocedure.

[0206]¹H-NMR (400 MHz, CDCl₃): 1.05 (t, 3H, J 7.5); 1.79-1.87 (m, 2H);2.55 (s, 3H); 3.98 (t, 2H, J 7.5); 6.92 (apparent d, 2H); 7.92 (apparentd, 2H).IR (ν_(max), cm¹, ATR): 1674s, 1599s, 1254s.MS [m/z (EI)]: 178(M⁺, 20%), 163 (18), 121 (100).

[0207] 1-(4-Decyloxy-phenyl)-ethanone

[0208] Obtained as a white solid according to the general procedure.

[0209] mp 33-34° C. (EtOH).

[0210]¹H-NMR (400 MHz, CDCl₃): 0.88 (t, 3H, J 7.5); 1.23-1.38 (m, 12H);1.40-1.50 (m, 2H); 1.74-1.83 (m, 2H); 2.54 (s, 3H); 4.00 (t, 2H, J 7.5);6.91 (apparent d, 2H); 7.91 (apparent d, 2H).IR (ν_(max), cm¹, ATR):2921s, 2852m, 1675s, 1605m, 1311s.MS [m/z (EI)]: 276 (M⁺, 28%), 261(18), 137 (43), 121 (100).

[0211] 1-(4-Octadecyloxy-phenyl)-ethanone

[0212] Obtained as a white solid according to the general procedure.

[0213] mp 69-70° C. (EtOH).

[0214]¹H-NMR (400 MHz, CDCl₃): 0.88 (t, 3H, J 7.5); 1.23-1.38 (m, 28H);1.40-1.49 (m, 2H); 1.75-1.84 (m, 2H); 2.55 (s, 3H); 4.01 (t, 2H, J 7.5);6.92 (apparent d, 2H); 7.92 (apparent d, 2H).IR (ν_(max), cm⁻¹, ATR):2920s, 2851S, 1676s, 1607m, 1256s.MS [m/z (EI)]: 388 (M⁺, 14%), 373 (6),137 (68), 121 (100).

[0215] 1-[4-(2-Methoxy-ethoxy)-phenyl]-ethanone

[0216] Obtained as a very pale yellow oil according to the generalprocedure.

[0217]¹H-NMR (400 MHz, CDCl₃): 2.54 (s, 3H); 3.45 (s, 3H); 3.75-3.78 (m,2H); 4.16-4.18 (m, 2H); 6.95 (apparent d, 2H); 7.92 (apparent d, 2H) IR(ν_(max), cm¹, ATR): 1673s, 1600s, 1254s. MS [m/z (EI)]: 194 (M+, 40%),179 (42), 121 (85), 59 (100).

[0218] 2. General Procedures for the Preparation of Compounds of theFormula I

[0219] Method A:

[0220] To a stirred solution of the acetophenone derivative (eitherfrom 1. or from commercial source, 0.2 mol) in dimethylsulfoxide (300ml) was added dropwise aqueous hydrobromic acid (47%, 70 ml, 0.6 mol, 3equiv.) within 40 minutes, during which the reaction temperature risedto 45° C. The resulting pale yellow to pale brown, clear mixture washeated at 55° C. for 5-10 h. The expense of starting material wasmonitored by TLC. After the reaction was completed, the formed dimethylsulfide was removed under reduced pressure (water aspirator) for 1 h at55° C. The mixture was allowed to cool and poured into ice/water (600ml), upon which the hydrated arylglyoxal precipitated. This was filteredoff, washed with water (3×150 ml) and dried in vacuo. (In some cases,the arylglyoxal hydrate does not precipitate, but can be isolated byextraction with ethyl acetate).

[0221] The crude arylglyoxal hydrate was dissolved in ethanol (abs., 300ml) and pyridinium toluene-4-sulfonate (2.5 g, 0.01 mol, max. 5 mol %)was added. The pale yellow to brown solution was heated to reflux andethanol (approx. 250 ml) was distilled off. Fresh ethanol (abs. 250 ml)was added and the procedure repeated 4 to 9 times. The completion of thereaction was monitored by TLC. The rection mixure was reduced to drynessin vacuo to give the intermediate α,α-diethoxy-acetophenone derivative.

[0222] To an aliquot of this residue [1/10, containing theα,α-diethoxy-acetophenone derivative (<0.02 mol) and pyridiniumtoluene-4-sulfonate (>0.001 mol, >5 mol %); or theα,α-di(m)ethoxy-acetophenone derivative from commercial source or theα,α-dimethoxy-acetophenone derivative from the general procedure B (seebelow) together with pyridinium toluene-4-sulfonate (5 mol %)] was addedthe alcohol (derived from the corresponding aldehyde or ketone, 0.06mol, 3 equiv.) and the resulting solution was heated at 100° C. for 6-36h, depending on the nature of the starting materials. The completion ofthe reaction was monitored by TLC. After cooling, the resulting yellowto dark brown suspension was diluted with hexane (100 ml) and washedwith water (2×50 ml) and brine (30 ml), dried (Na₂SO₄) and concentratedin vacuo. The excess alcohol was distilled off under reduced pressure(0.1 mbar) in a ‘Kugelrohr’ apparatus. The residue was diluted withhexane (10 ml) and treated with activated charcoal (1 to 3 g). Thesuspension was heated to reflux for 1 to 2 h, cooled and filteredthrough a plug of Celite® and concentrated in vacuo to afford therequired Aroyl-Formaldehyde Acetal (generally >90% purity).

[0223] Method B:

[0224] A mixture of the acetophenone derivative (0.1 mol), diphenyldiselenide (16 g, 0.05 mol, 0.5 equiv.) and ammonium peroxydisulfate(68.5 g, 0.3 mol, 3 equiv.) in methanol (600 ml) was heated to refluxand stirred for 1 to 2 h. The completion of the reaction was monitoredby TLC or GLC. Methanol was removed in vacuo and the yellow to brownresidue taken up in water (200 ml). This was extracted with MTBE (2×200ml) and the organic phases each washed with water (200 ml) and brine(100 ml), combined, dried (Na₂SO₄) and concentrated in vacuo. The crudeproduct was filtered through a plug of silica and diphenyl diselenidewas eluted with hexane (1000 to 2000 ml) and isolated (this could berecycled several times with only moderate loss). Further elution of thesilica plug with either MTBE or ethyl acetate (depending on the natureof the product) and concentration of the filtrate in vacuo afforded thedesired α,α-dimethoxy-acetophenone derivative in 75-80% yield. In somecases, when the product was dark yellow to brown, a charcoal treatmentwas adequat.

[0225] The trans-acetalisation was performed as descibed under method A.

[0226] 3. Representative Selection of Compounds of Formula I.

[0227] 1-Phenyl-2,2-bis-undec-10-enyloxy-ethanone

[0228] Obtained as a very pale yellow oil from 10-undecen-1-ol andcommercial α,α-diethoxy-acetophenone according to method A.

[0229]¹H-NMR (400 MHz, CDCl₃): 1.20-1.38 (m, 24H); 1.55-1.63 (m, 4H);2.02 (q, 4H, J 7); 3.55-3.59 (m, 2H); 3.66-3.70 (m, 4H); 4.92 (apparentd, 2H, J 9.5); 4.98 (apparent d, 2H, J 17); 5.22 (s, 1H); 5.80 (ddt, 2H,J 17, 9.5, 3); 7.43 (apparent t, 2H, J 7.5); 7.54 (apparent t, 1H, J7.5); 8.16 (apparent d, 2H, J 7.5).IR (ν_(max), cm⁻¹, ATR): 3075w,2925s, 2855m, 1689m, 1070s.MS [m/z (EI)]: 457 ([M+H]⁺, 1%), 351 (10),111 (21), 105 (14), 97 (77), 83 (56), 69 (100), 55 (45).UV [λ_(max) innm (ε), EtOH]: 283sh (1740), 248 (12930).

[0230] 1-(4-Methoxy-phenyl)-2,2-bis-undec⁻¹⁰-enyloxy-ethanone

[0231] Obtained as a very pale yellow oil from 10-undecen-1-ol andacetanisole according to method A.

[0232]¹H-NMR (400 MHz, CDCl₃): 1.20-1.39 (m, 24H); 1.56-1.64 (m, 4H);2.02 (q, 4H, J 7); 3.53-3.58 (m, 2H); 3.65-3.69 (m, 2H); 3.86 (s, 3H);4.92 (apparent d, 2H, J 9.5); 4.98 (apparent d, 2H, J 17); 5.17 (s, 1H);5.80 (ddt, 2H, J 17, 9.5, 3); 6.91 (apparent d, 2H, J 9); 8.16 (apparentd, 2H, J 9).IR (ν_(max), cm⁻¹, ATR): 3078w, 2925s, 2854m, 1681m, 1600s,1258s.MS [m/z (EI)]: 487 ([M+H]⁺, 1%), 351 (71), 153 (44), 135 (74), 111(75), 105 (14), 97 (100), 83 (93), 69 (83), 55 (87).UV [λ_(max) in nm(ε), EtOH]: 284 (12500), 222 (8100).

[0233] 2,2-Bis-phenethyloxy-1-(4-propoxy-phenyl)-ethanone

[0234] Obtained as a very pale yellow oil from phenethylalcohol and1-(4-propoxy-phenyl)-ethanone according to method A.

[0235]¹H-NMR (400 MHz, CDCl₃): 1.04 (t, 3H, J 7); 1.77-1.88 (m, 2H);2.86 (t, 4H, J 7); 3.68-3.75 (m, 2H); 3.78-3.85 (m, 2H); 3.96 (t, 2H, J6.5); 5.20 (s, 1H); 6.83 (apparent d, 2H, J 9); 7.12-7.27 (m, 10H); 8.00(apparent d, 2H, J 9). IR (ν_(max), cm⁻¹, ATR): 1678m, 1599s, 1064s. MS[m/z (EI)]: 418 (M⁺, <1%), 255 (12), 163 (31), 121 (43), 105 (100), 91(23). UV [λ_(max) in nm (ε), EtOH]: 286 (17160).

[0236]2,2-Bis-(2-isopropyl-5-methyl-cyclohexyloxy)-1-(4-propoxy-phenyl)-ethanone

[0237] Obtained as a very pale yellow oil from (−)-menthol and1-(4-propoxy-phenyl)-ethanone according to method A.

[0238]¹H-NMR (400 MHz, CDCl₃): 0.44 (d, 3H, J 7), 0.75 (d, 3H, J 7),0.75-1.07 (m, 22H); 1.08-1.41 (m, 5H); 1.53-1.67 (m, 4H); 1.77-1.87 (m,2H); 2.19-2.25 (m, 1H); 2.36-2.45 (m, 1H); 3.24 (td, 1H, J 10.5, 4);3.49 (td, 1H, J 11, 4.5); 3.93 (t, 2H, J 6.5); 5.05 (s, 1H); 6.89(apparent d, 2H, J 9); 8.21 (apparent d, 2H, J 9). IR (ν_(max), cm⁻¹,ATR): 2954m, 2922m, 1677m, 1600s, 1256s, 1064s. MS [m/z (EI)]: 486 (M⁺,<1%), 323 (3), 163 (28), 139 (85), 121 (19), 83 (100), 57 (40). UV[λ_(max) in nm (ε), EtOH]: 285 (17920), 222 (10610).

[0239]2,2-Bis-[1-methyl-3-(2,6,6-trimethyl-cyclohex-1-enyl)-propoxy]-1-(4-propoxy-phenyl)-ethanone

[0240] Obtained as mixture of diastereoisomers (a pale yellow oil) fromracemic β-dihydroionone and 1-(4-propoxy-phenyl)-ethanone according tomethod A.

[0241]¹H-NMR (400 MHz, CDCl₃): 0.81-0.86 (m, 6H), 0.98-1.05 (m, 9H),1.13 (m, 3H); 1.28-1.95 (m, 29H); 1.96-2.07 (m, 1H); 2.23-2.33 (m, 1H);3.61-3.73 (m, 1H); 3.77-3.86 (m, 1H); 3.94-4.00 (m, 2H); 5.04, 5.06,5.07 (3×s, 1H); 6.88 (apparent d, 2H, J 9); 8.26 (apparent d, 2H, J 9).IR(ν_(max), cm¹, ATR) 2928m, 1678m, 1600s, 1257s, 1022s. MS [m/z (EI)]:566 (M⁺, <1%), 403 (3), 179 (61), 163 (52) 137 (100), 123 (84), 109(76), 95 (91), 81 (56). UV [λ_(max) in nm (ε), EtOH]: 284 (16550).

[0242]1-(4-Decyloxy-phenyl)-2,2-bis-(3,7-dimethyl-oct-6-enyloxy)-ethanone

[0243] Obtained as a pale yellow oil from citronellol and1-(4-decyloxy-phenyl)-ethanone according to method A.

[0244]¹H-NMR (400 MHz, CDCl₃): 0.83-0.91 (m, 9H); 1.08-1.19 (m, 2H);1.20-1.40 (m, 14H); 1.40-1.48 (m, 4H); 1.50-1.71 (m, 4H); 1.57 (s, 6H);1.66 (s, 6H); 1.83-1.94 (m, 2H); 1.95-2.04 (m, 4H); 3.55-3.62 (m, 2H);3.68-3.75 (m, 2H); 4.00 (t, 2H, J 6.5); 5.05 (apparent t, 2H, J 7.5);5.16 (s, 1H); 6.89 (apparent d, 2H, J 9); 8.14 (apparent d, 2H, J 9). IR(ν_(max), cm⁻¹, ATR): 2924s, 2855m, 1681m, 1600s, 1255s. MS [m/z (EI)]:584 (M⁺, <1%), 430 (1), 292 (2), 261 (8) 139 (38), 121 (23), 83 (100),69 (72), 57 (41). UV [λ_(max) in nm (ε), EtOH]: 286 (17210), 223 (9790).

[0245]2,2-Bis-[3-(4-tert-butyl-phenyl)-2-methyl-propoxy]-1-(4-octadecyloxy-phenyl)-ethanone

[0246] Obtained as mixture of diastereoisomers (a pale brown solid) from3-(4-tert-butyl-phenyl)-2-methyl-propan-1-ol and1-(4-octadecyloxy-phenyl)-ethanone according to method A.

[0247] mp 40-42° C.

[0248]¹H-NMR (400 MHz, CDCl₃): 0.86-0.90 (m, 9H); 1.23-1.39 (m, 46H);1.40-1.49 (m, 2H); 1.73-1.82 (m, 2H); 1.99-2.08 (m, 2H); 2.29-2.39 (m,2H); 2.65-2.75 (m, 2H); 3.32-3.43 (m, 2H); 3.50-3.61 (m, 2H); 4.00 (t,2H, J 6.5); 5.06, 5.09, 5.10 (3×s, 1H); 6.91 (apparent d, 2H, J 9); 7.03(apparent t, 4H, J 9); 7.22-7.28 (m, 4H); 8.16-8.21 (m, 2H). IR(ν_(max), cm¹, ATR): 2924s, 2853s, 1681m, 1600s, 1256s. MS [m/z (EI)]:592 ([M-Lilial®]⁺, <1%), 576 (2), 423 (1), 388 (7), 206 (18), 191 (97),131 (68), 91 (57), 57 (100). UV [λ_(max) in nm (ε), EtOH]: 286 (15850),222 (24680).

[0249]2,2-Bis-(2,4-dimethyl-cyclohex-3-enylmethoxy)-1-(4-propoxy-phenyl)-ethanone

[0250] Obtained as mixture of diastereoisomers (a pale brown oil) from(2,4-dimethyl-cyclohex-3-enyl)-methanol and1-(4-propoxy-phenyl)-ethanone according to method A.

[0251]¹H-NMR (400 MHz, CDCl₃): 0.87-1.01 (m, 6H); 1.04 (t, 3H, J 7);1.34-1.48 (m, 4H); 1.62 (apparent s, 6H); 1.77-2.01 (m, 10H); 3.39-3.44(m, 1H); 3.56-3.65 (m, 2H); 3.74-3.79 (m, 1H); 3.99 (t, 2H, J 6.5);5.05-5.30 (m, 3H); 6.90 (apparent d, 2H, J 9); 8.14 (apparent d, 2H, J9). IR (ν_(max) cm ¹, ATR): 2960m, 2924m, 2873m, 1680m, 1599s, 1257s. MS[m/z (EI)]: 454 (M⁺, <1%), 315 (1), 291 (5), 163 (20), 151 (62), 123(100), 81 (88), 67 (55), 57 (29). UV [λ_(max) in nm (ε), EtOH]: 285(17020), 222 (9390).

[0252]1-[4-(2-Methoxy-ethoxy)-phenyl]-2,2-bis-(2,6,10-trimethyl-undec-9-enyloxy)-ethanone

[0253] Obtained as mixture of diastereoisomers (a pale brown oil) from2,6,10-trimethyl-undec-9-en-1-ol and1-[4-(2-methoxy-ethoxy)-phenyl]-ethanone according to method B.

[0254]¹H-NMR (400 MHz, CDCl₃): 0.84 (d, 6H, J 6.5); 0.88-0.91 (m, 6H);0.98-1.45 (m, 18H); 1.59 (apparent s, 6H); 1.68 (apparent s, 6H);1.70-1.78 (m, 2H); 1.86-2.04 (m, 4H); 3.29-3.34 (m, 1H); 3.37-3.50 (m,2H); 3.44 (s, 3H); 3.53-3.59 (m, 1H); 3.75 (t, 2H, J 4.5); 4.17 (t, 2H,J 4.5); 5.04-5.13 (m, 3H); 6.94 (apparent d, 2H, J 9); 8.15 (apparent d,2H, J 9). IR (ν_(max), cm⁻¹, ATR): 2924s, 2872m, 1681m, 1600s, 1293s. MS[m/z (EI)]: 615 ([M+H]⁺, <1%), 435 (13), 404 (8), 209 (20), 195 (18),179 (40), 139 (75), 125 (76), 113 (86), 97 (85), 83 (100), 69 (93), 57(88). UV [λ_(max) in nm (6), EtOH]: 284 (12850), 221 (5970).

[0255]1-[4-(2-Methoxy-ethoxy)-phenyl]-2,2-bis-(2-methyl-undecyloxy)-ethanone

[0256] Obtained as mixture of diastereoisomers (a pale yellow oil) from2-methyl-undecan-1-ol and 1-[4-(2-methoxy-ethoxy)-phenyl]-ethanoneaccording to method A or B.

[0257]¹H-NMR (400 MHz, CDCl₃): 0.86-0.92 (m, 12H); 1.02-1.15 (m, 2H);1.16-1.42 (m, 30H); 1.67-1.78 (m, 2H); 3.30 (dd, 1H, J 9, 6.5);3.38-3.48 (m, 2H); 3.44 (s, 3H); 3.52-3.57 (m, 1H); 3.76 (dd, 2H, J 4.5,3.5); 4.17 (dd, 2H, J 4.5, 3.5); 5.08, 5.09, 5.1 (3×s, 1H); 6.94(apparent d, 2H, J 9); 8.15 (apparent d, 2H, J 9). IR (ν_(max), cm⁻¹,ATR): 2923s, 2854s, 1682m, 1601s, 1257s. MS [m/z (EI)]: 563 ([M+H]⁺,<1%), 383 (12), 209 (21), 179 (52), 169 (100), 127 (30), 121 (38), 113(73), 99 (95), 85 (98), 71 (99), 57 (96), 43 (76). UV [(λ_(max) in nm(ε), EtOH]: 283 (15190), 222 (8670).

[0258]1-(4-Methylsulfanyl-phenyl)-2,2-bis-(2-methyl-undecyloxy)-ethanone

[0259] Obtained as mixture of diastereoisomers (a pale yellow oil) from2-methyl-undecan-1-ol and 4′-(methylthio)-acetophenone according tomethod B.

[0260]¹H-NMR (400 MHz, CDCl₃): 0.84-0.94 (m, 12H); 1.05-1.17 (m, 2H);1.17-1.43 (m, 30H); 1.69-1.78 (m, 2H); 2.76 (s, 3H); 3.34 (dd, 1H, J 9,6.5); 3.39-3.47 (m, 1H); 3.48-3.56 (m, 1H); 3.58-3.64 (m, 1H); 5.06,5.065, 5.07 (3×s, 1H); 7.72 (apparent d, 2H, J 8.5); 8.33 (apparent d,2H, J 9). IR (ν_(max), cm¹, ATR): 2923s, 2853m, 1694m, 1591w, 1053s. MS[m/z (EI)]: 533 ([M−H]⁻, 6%), 505 (12), 383 (10), 197 (17), 169 (100),151 (41), 127 (30), 113 (69), 99 (84), 85 (85), 71 (83), 57 (77), 43(71). UV [λ_(max) in nm (ε), EtOH]: 271 (6320), 240 (9100).

[0261]2,2-Bis-(2,6-dimethyl-hept-5-enyloxy)-1-(3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanone

[0262] Obtained as mixture of diastereoisomers (a yellow gum) from2,6-dimethyl-hept-5-en-1-ol and1-(3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)-ethanoneaccording to method B.

[0263]¹H-NMR (400 MHz, CDCl₃): 0.89-0.92 (m, 6H); 0.99 (d, 3H, J 7);1.07 (s, 3H); 1.07-1.19 (m, 2H); 1.26 (s, 3H); 1.31 (s, 3H); 1.40 (s,3H); 1.36-1.49 (m, 3H); 1.56 (s, 6H); 1.58-1.81 (m, 4H); 1.65 (s, 6H);1.83-2.04 (m, 4H); 2.50 (s, 3H); 3.34 (dd, 1H, J 9, 6.5); 3.40-3.49 (m,2H); 3.50-3.57 (m, 1H); 5.01-5.07 (m, 3H); 7.18 (s, 1H); 8.14 (s, 1H).IR (ν_(max), cm⁻¹, ATR): 2964s, 2912m, 1679m, 1455m, 1053s. MS [m/z(EI)]: 538 (M⁺, <1%), 397 (1), 295 (2), 243 (34), 125 (75), 83 (47), 69(100), 57 (53), 41 (33). UV [λ_(max) in nm (ε), EtOH]: 298sh (1140), 264(14250).

[0264]2,2-Bis-[3-(3-isopropyl-phenyl)-butoxy]-1-naphthalen-2-yl-ethanone

[0265] Obtained as mixture of diastereoisomers (a pale yellow gum) from3-(3-isopropyl-phenyl)-butan-1-ol and 1-naphthalen-2-yl-ethanoneaccording to method A.

[0266]¹H-NMR (400 MHz, CDCl₃): 1.03-1.27 (m, 18H); 1.83-1.92 (m, 4H);2.73-2.91 (m, 4H); 3.41-3.53 (m, 2H); 3.55-3.72 (m, 2H); 5.17, 5.175,5.18 (3×s, 1H); 6.88-7.03 (m, 6H); 7.11-7.18 (m, 2H); 7.50 (apparent t,1H, J 7); 7.55 (apparent t, 1H, J 7); 7.82 (apparent d, 1H, J 8); 7.85(apparent d, 1H, J 8.5); 7.96 (apparent d, 1H, J 8); 8.16 (apparent d,1H, J 8.5); 8.80 (s, 1H). IR (ν_(max), cm⁻¹, ATR): 2958m, 1687m, 1487m,1050s. MS [m/z (EI)]: 532 (<1%), 395 (21), 175 (86), 155 (24), 147 (57),133 (100), 105 (47), 91 (67), 43 (34). UV [λ_(max) in nm (ε), EtOH]286/295 (4150), 252 (32530), 209 (32280).

[0267] 2,2-Bis-(2-methyl-undecyloxy)-1,2-diphenyl-ethanone

[0268] Obtained as mixture of diastereoisomers (a pale yellow oil) from2-methyl-undecan-1-ol and 2,2-dimethoxy-2-phenyl-acetophenone accordingto method A.

[0269]¹H-NMR (400 MHz, CDCl₃): 0.85-0.94 (m, 12H); 1.05-1.41 (m, 32H);1.66-1.75 (m, 2H); 3.07-3.14 (m, 2H); 3.18-3.29 (m, 2H); 7.22-7.39 (m,6H); 7.62 (apparent d, 2H, J 7.5); 8.02 (apparent d, 2H, J 7.5). IR(ν_(max), cm¹, ATR): 2923s, 2853m, 1698m, 1448m, 1055s. MS [m/z (EI)]:459 ([M-PhCO]⁺, 13%), 291 (43), 211 (23), 169 (76), 123 (100), 105 (75),85 (78), 71 (83), 57 (88), 43 (77). UV [λ_(max) in nm (ε), EtOH] 252(12750).

[0270] 1-(3,4-Dimethoxy-phenyl)-2,2-bis-(2-methyl-undecyloxy)-ethanone

[0271] Obtained as mixture of diastereoisomers (a yellow oil) from2-methyl-undecan-1-ol and 1-(3,4-dimethoxy-phenyl)-ethanone according tomethod B.

[0272]¹H-NMR (400 MHz, CDCl₃): 0.84-0.92 (m, 12H); 1.05-1.17 (m, 2H);1.17-1.43 (m, 30H); 1.69-1.78 (m, 2H); 3.33 (dd, 1H, J 9, 6.5); 3.42(dd, 1H, J 9, 5.5); 3.45-3.52 (m, 1H); 3.54-3.59 (m, 1H); 3.93 (S, 3H);3.94 (s, 3H); 5.09, 5.10, 5.11 (3×s, 1H); 6.94 (apparent d, 1H, J 8.5);7.71 (d, 1H, J 2); 7.91 (dd, 1H, J 8.5, 2). IR (ν_(max), cm¹, ATR):2923s, 2854m, 1680m, 1595m, 1271s. MS [m/z (EI)]: 548 (M⁺, <1%), 383(5), 195 (9), 169 (56), 165 (17), 113 (32), 99 (54), 85 (70), 71 (87),57 (100), 43 (37). UV [λ_(max) in nm (ε), EtOH]: 310 (8480), 279(10280), 231 (15060).

[0273]1-Benzo[1,3]dioxol-5-yl-2,2-bis-[3-(4-tert-butyl-phenyl)-2-methyl-propoxy]-ethanone

[0274] Obtained as mixture of diastereoisomers (a pale brown oil) from3-(4-tert-butyl-phenyl)-2-methyl-propan-1-ol and1-benzo[1,3]dioxol-5-yl-ethanone according to method B.

[0275]¹H-NMR (400 MHz, CDCl₃): 0.86-0.91 (m, 6H); 1.29 (m, 18H);1.99-2.07 (m, 2H); 2.29-2.39 (m, 2H); 2.66-2.74 (m, 2H); 3.32-3.43 (m,2H); 3.50-3.62 (m, 2H); 5.04, 5.05, 5.06 (3×s, 1H); 6.01 (s, 2H); 6.85(apparent d, 1H, J 8.5); 7.04 (apparent t, 4H, J 9); 7.24-7.29 (m, 4H);7.65-7.68 (m, 1H); 7.87-7.93 (m, 1H). IR (ν_(max), cm⁻¹, ATR): 2924m,1681m, 1259s, 1039s. MS [m/z (EI)]: 572 (M⁺, <1%), 423 (12), 189 (95),147 (94), 131 (20), 57 (100). UV [λ_(max) in nm (ε), EtOH]: 314 (6870),277 (5890), 219 (26220).

[0276]2,2-Bis-[3-(4-tert-butyl-phenyl)-2-methyl-propoxy]-1-(4-diethylamino-phenyl)-ethanone

[0277] Obtained as mixture of diastereoisomers (an orange-brown oil)from 3-(4-tert-butyl-phenyl)-2-methyl-propan-1-ol and1-(4-diethylamino-phenyl)-ethanone according to method B.

[0278]¹H-NMR (400 MHz, CDCl₃): 0.85-0.92 (m, 6H); 1.18-1.21 (m, 6H);1.29 (s, 18H); 2.00-2.09 (m, 2H); 2.28-2.40 (m, 2H); 2.69-2.80 (m, 2H);3.32-3.48 (m, 6H); 3.50-3.61 (m, 2H); 5.10, 5.12, 5.13 (3×s, 1H); 6.01(s, 2H); 6.60-6.64 (m, 2H); 7.03-7.10 (m, 4H); 7.25-7.29 (m, 4H);8.04-8.13 (m, 2H). IR (ν_(max), cm¹, ATR): 2964m, 1665m, 1593s, 1196m,1076m. MS [m/z (EI)]: 599 (M⁺, <1%), 423 (8), 395 (4), 189 (87), 147(82), 131 (21), 57 (100). UV [λ_(max) in nm (ε), EtOH]: 350 (9230), 245(1600), 218sh (7060).

EXAMPLE 2

[0279] Photolysis of Compounds of Formula I (Aroyl-Formaldehyde Acetals)in Solution

[0280] Photolysis experiments were conducted on solutions (typicalconcentrations of compounds of formula I: 0.1% w/v in ethanol). Thesolutions were irradiated with a mercury lamp (150 W) in a borosilicateglass apparatus (Pyrex®) so as to limit the irradiation window to mainlythe UVA and UVB spectrum (>300 nm). The alcoholic solution wasirradiated for one to three hours and samples taken every 15 min toanalyze the extent of the photolysis. The presence of the aryl ketone(II) and aldehyde/ketone (III) after photolysis in solutions (1 inethanol abs.) was determined by using GLC retention times. Samples (2μl) were injected (on column injection) without further dilution. Gaschromatography-flame ionisation detection (GC-FID) was carried out witha CE-Instruments TraceGC 2000 apparatus, using a Supelco Simplicity-1fused silica capillary column (15 m, 0.53 mm id, 1.5 μm film, He carriergas, 50 kPa). A typical temperature program consists of injecting at100° C., heating at 30° C./min to 300° C. and keeping this temperaturefor 60 min. The retention times of the Aroyl-Formaldehyde Acetals (I)vary from 10 to 30 minutes. The results after 15 minutes of irradiationare given in table 1. The rate of cleavage was established according tochromophores (II):Fixolide®>deoxybenzoin˜p-alkoxy-acetophenones˜p-methylthio-acetophenone>p-(2-methoxyethoxy)-acetophenones>acetophenone>>m,p-dialkoxy-acetophenones>>2′-acetonaphthone;and according to the aldehyde/ketone(III): aldehydes>>ketones. The lowrecovery of fragrance [generally below 2% of (II) and below 15% of (III)at complete conversion] is due to the instability towards free radicalswhich are constantly generated under these severe irradiationconditions. TABLE 1 Release of aryl ketones (II) and aldehydes/ketones(III) from Aroyl-Formaldehyde Acetals (I) in solution upon 15 minutes ofirradiation Aldehyde/ Aroyl-Formaldehyde Acetal Aryl ketone Ketoneunreacted (I) (II) (III) (I) 1

Fixolide ®<0.1% Lilial ®3.0%  1.9% 2

Oranger Crystals ®<0.1% Lilial ®1.4% 94.9% 3

Acetophenone 1.6% Lilial ®13.4% 34.5% 4

Acetanisole <0.1% Lilial ®12.2% 12.5% 5

<0.1% (−)-Menthone 9.4% 33.5% 6

<0.1% Lilial ®13.8% 12.0% 7

<0.1% Lilial ®8.1% 28.2% 8

<0.1% Lilial ®8.1% 12.7% 9

<0.1% Lilial ®4.3% 71.4% 10

<0.1% Lilial ®1.1%   9% 11

<0.1% Lilial ®0.8% 95.9%

EXAMPLE 3

[0281] Photorelease Assays on Fabric: Spray Tests

[0282] 1 g of an approximately 0.2% Aroyl-Formaldehyde Acetals (I)solution in ethanol was evenly sprayed on a Terry towel (white cottontowel, 25 cm×25 cm, 45 g), corresponding to 45-75 μg/g cotton. Thesprayed towels were allowed to dry in a dark and odorless place. Whendry, a first towel was irradiated for a few seconds up to a few minuteswith a tanning lamp (Osram Ultra-Vitalux®, 300 W; at a distance of 50cm, the light has approximately six to seven times the effect of thenatural sunlight at noon on a sea-side mid-summer day or an energy of1.9 mW/cm²). A second towel was exposed for several minutes upto onehour to natural western European winter sun light behind an ordinaryglass window (0.1-0.2 mW/cm²). The evaluation was done by a trainedpanel of perfumers before and after light exposure. Before irradiation,the towels were judged to be odorless. The results after irradiation aresummarized in table 2. TABLE 2 Release of aryl ketones (II) andaldehydes/ketones (III) from Aroyl-Formaldehyde Acetals (I) on fabricupon irradiation with a tanning lamp. Fragrance Target (perception)*Global Aryl ketone Aldehyde/ apprecia- (II) Ketone (III) tion*Aroyl-Formaldehyde art. nat. art. nat. art. nat. Acetal (I) light lightlight light light light 1

Fioxolide ® Lilial ® +++ ++ +++ ++ +++ + + 2

Fixolide ® Melonal ® +++ ++ +++ ++ ++ + 3

Oranger Crystals ® Lilial ® ++ 0 ++ 0 ++ 0 4

Oranger Crystals ® Citronellal ++ 0 ++ 0 ++ + 5

Oranger Crystals ® Florhydral ® + 0 ++ 0 + 0 6

Oranger Crystals ® 10-Undecenal ++ 0 ++ 0 ++ 0 4

Acetanisole Lilial ® +++ ++ +++ ++ +++ ++ 5

Acetanisole Citronellal +++ ++ +++ ++ +++ ++ 6

Acetanisole Florhydral ® ++ + +++ ++ ++ + 7

Acetanisole 10-Undecenal +++ ++ +++ ++ +++ ++ 8

no fragrance ingredient Lilial ® +++ ++ +++ ++ 9

no fragrance ingredient 2-Methyl-un- decanal +++ +++ +++ +++ 10

no fragrance ingredient Phenyl- acetaldehyde +++ +++ +++ ++ 11

no fragrance ingredient Cyclal C ® +++ + +++ + 12

no fragrance ingredient Adoxal ® ++ + ++ + 13

no frangrance ingredient (−)-Menthone ++ + ++ + 14

no fragrance ingredient β-Dihydro- ionone ++ 0 ++ 0 15

no fragrance ingredient Lilial ® +++ ++ +++ ++ 16

no fragrance ingredient 2-Methyl-un- decanal +++ +++ +++ +++ 17

no fragrance ingredient Cyclal C ® +++ + +++ + 18

no fragrance ingredient Adoxal ® ++ + ++ + 19

no fragrance ingredient Citronellal +++ ++ +++ ++ 20

no fragrance ingredient 10-Undecenal +++ ++ +++ ++ 21

no fragrance ingredient Lilial ® +++ ++ +++ ++ 22

no fragrance ingredient Citronellal +++ ++ +++ ++ 23

no fragrance ingredient Florhydral ® + 0 + 0 24

no fragrance ingredient 10-Undecenal +++ ++ +++ ++ 25

Acetophenone Lilial ® ++ + ++ + ++ + 26

Acetanisole Citronellal ++ + ++ + ++ + 27

Acetanisole 10-Undecenal ++ + ++ + ++ + 28

no fragrance ingredient Hexanal ++ + ++ + 29

no fragrance ingredient 2-Methyl-un- decanal +++ +++ +++ ++ 30

no fragrance ingredient Lilial ® ++ + ++ + 31

no fragrance ingredient Lilial ® ++ + ++ + 32

no fragrance ingredient 2-Methyl-un- decanal +++ + +++ + 33

no fragrance ingredient Lilial ® +++ ++ +++ ++ 34

no fragrance ingredient 2-Methyl-un- decanal +++ +++ +++ +++ 35

no fragrance ingredient Phenyl- acetaldehyde ++ + ++ ++ 36

no fragrance ingredient Cyclal C ® ++ + ++ + 37

no fragrance ingredient Lilial ® +++ ++ +++ ++ 38

no fragrance ingredient 2-Methyl-un- decanal +++ ++ +++ ++ 39

no fragrance ingredient Phenyl- acetaldehyde ++ + ++ + 40

no fragrance ingredient Cyclal C ® ++ + ++ + 41

no fragrance ingredient Lilial ® + 0 + 0 42

Lilial ® +++ +++ 43

Aldehyde C12MNA +++ +++

EXAMPLE 4

[0283] Stability Tests

[0284] Aroyl-Formaldehyde Acetals (I) were incubated in aqueous buffersolutions of pH 2.5, pH 7 and pH 9.5 for 24 h at 37° C. and were foundto be stable in acida (pH<4), basic (pH>9) and neutral (pH 4-9) media.The results are summarized in table 3. TABLE 2 Stability ofAroyl-Formaldehyde Acetals (I) under different pHs Aroyl-FormaldehydeAcetal (I) pH 2.5 pH 7 pH 9.5 1

stable stable stable 2

stable stable stable

EXAMPLE 5

[0285] Preparation of an O/W Sunscreen Lotion UV-B and UV-A:

[0286] Sunscreen lotion containing 0.5% of perfume comprising one ormore compounds of formula I of Example 1.

[0287] Recipe: Ingredients % Part A Octyl methoxycinnamate 2.04-tert-butyl-4′methoxydibenzoyl methane 3.0 Isostearyl neopentanoate 4.0Coco-caprylate/caprate 12.0 Diethyleneglycol monostearate 0.25Cetylalcohol 1.0 Methyl-propylparabene 0.25 EDTA-sodium salt 0.1Diethanolamine cetylphosphate 1.0 Perfume 0.5 Part B Acrylate C10-C30Alkylacrylate 20.0 water 50.1 1,2-Propanediol 5.0 Potassium hydroxide0.8

[0288] Process: Part A was heated in a reactor to 85° C. Part B wasslowly added within 10 min. The emulsion was then cooled and degassed.

EXAMPLE 6

[0289] Fabric softeners (otherwise known as rinse conditioners)containing 0.5-0.7% perfume comprising one or more compounds of formulaI of Example 1.

[0290] a) Fabric Softener of the Ester Quat Type (4× Concentrate)Ingredients % PHASE A WATER 77.78 aqueous MgCl₂ (sat. soln.) 1.0 PHASE BREWOQUAT WE 18 15.0 GENAPOL O 100 2.0 ANTIFOAM DB 31 0.5 PHASE CISOPROPYL ALCOHOL 3.0 PRESERVATIVE 0.02 PERFUME* 0.7

[0291] PROCESS: While stirring and heating to 65° C., mix phase A, thenphase B preheated to 65° C. After cooling to room temperature, add phaseC. The pH value of the finished product is 2.60. Perfume*: one ore moreof the compounds of formula I of Example 1 may be any part of this 0.7%.

[0292] b) Fabric Softener of the Ester Quat Type (1× Concentrate):Ingredients % PHASE A WATER 92.85 PHASE B REWOQUAT WE 18 6.0 DOBANOL25-9 0.5 ANTIFOAM DB 31 0.1 PHASE C MYACIDE BT 30 0.03 PROXEL GXL 0.02PERFUME* 0.5

[0293] PROCESS: While stirring and heating to 65° C., mix phase A, thenphase B preheated to 65° C. After cooling to room temperature, add phaseC. The pH value of the finished product is 3.50. Perfume*: compounds offormula I of Example 1 may be any part of this 0.5%.

EXAMPLE 7

[0294] Heavy duty detergents containing perfume comprising one or morecompounds of formula I of Example 1.

[0295] a) Heavy Duty Liquid Detergent (Regular) Ingredients %SURFACTANTS 21.5 AS/AEOS 9.5 SOAPS/FATTY ACIDS 7.1 NON-IONICS-AEO 3.1NON-IONICS-FAGA 1.8 SODIUM CHLORIDE 1.6 BORAX 1.7 SODIUM CIT/CITRIC ACID1.2 PHOSPHONATES 0.3 WATER 47.5 ETHANOL 0.6 MPG 3.4 PERFUME* 0.7

[0296] b) Heavy Duty Detergent Powder (Regular) Ingredients %SURFACTANTS 12.1 LAS/PS 4.0 SOAPS/FATTY ACIDS 4.3 NON-IONICS-AEO 3.1 P-P2.6 STPP 17.3 SODIUM SULPHATE 21.3 SODIUM CARBONATE 15.3 SODIUM CHLORIDE1.1 SODIUM SILICATE 5.3 ZEOLITES 2.1 POLYMERS - PCA 2.1 PERBORATES (SPT)8.9 PERFUME* 0.5

1. Use of a compound of the formula I

as precursor for a ketone of the formula II,

an aldehyde or ketone of the formula III comprising up to 20 carbonatoms, and

an aldehyde or ketone of the formula IV comprising up to 20 carbonatoms,

wherein A is an aromatic or a heteroaromatic ring; or A is an aromaticor heteroaromatic ring substituted with one or more residues selectedfrom the group of alkyl, aryl, aralkyl, alkenyl, alkynyl, —OH, —O-alkyl,-alkoxyalkoxy, —O-aralkyl, —O-aryl, —O-acyl, —NO₂, —NH₂, —NH-alkyl,—N(alkyl)₂, —NH-acyl, —N(acyl)₂, —CN, —SH, —S-alkyl, —S-aryl and ahalogen atom, selected from fluorine, chlorine or bromine; or A is anaromatic or heteroaromatic ring bearing a residue that together with thecarbon atoms to which it is attached forms an aromatic or alicyclicring, or an aromatic or alicyclic ring bearing one or more heteroatomsselected from oxygen, nitrogen or sulphur, which aromatic or alicyclicring may be substituted with one or more residues selected from thegroup of alkyl, alkenyl, and alkynyl residues, R¹ represents hydrogen,alkyl, alkenyl, alkynyl, acyl or aryl residues, and said residues maycomprise one or more oxygen atom(s), R², R³, R⁴, R⁵ representindependently hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkenyl or aromatic residues, and said residues may comprise one ormore oxygen atom(s), R² and R³ together with the carbon atom to whichthey are attached may form a 4 to 18 membered carbocyclic ringoptionally substituted by an alkyl, alkenyl or alkynyl residue having upto 10 carbon atoms, and the ring and residues may comprise one or moreoxygen atom(s), R⁴ and R⁵ together with the carbon atom to which theyare attached may form a 4 to 18 membered carbocyclic ring optionallysubstituted by an alkyl, alkenyl or alkynyl residue having up to 10carbon atoms, and the ring and residues may comprise one or more oxygenatom(s), and n is an integer from 1 to
 3. 2. Use of a compound offormula I according to claim 1 wherein A is phenyl; or A is phenylsubstituted with one or more residues selected from the group of alkyl,aryl, aralkyl, alkenyl, alkynyl, —OH, —O-alkyl, -alkoxyalkoxy,—O-aralkyl, —O-aryl, —O-acyl, —NO₂, —NH₂, —NH-alkyl, —N(alkyl)₂,—NH-acyl, —N(acyl)₂, —CCN, —SH, —S-alkyl, —S-aryl and a halogen atom,selected from fluorine, chlorine or bromine; or A is phenyl bearing aresidue that together with the carbon atoms to which it is attachedforms an aromatic or alicyclic ring, or an aromatic or alicyclic ringbearing one or more heteroatoms selected from oxygen, nitrogen orsulphur, which aromatic or alicyclic ring may be substituted with one ormore residues selected from the group of alkyl, alkenyl, and alkynylresidues.
 3. Use of a compound of formula I according to one of theclaims 1 to 2, wherein n=1, R² and R⁴ are independently an alkyl,alkenyl, alkynyl residue having 5 to 17 carbon atoms and R³ and R⁵ areH.
 4. Use of a compound of formula I according to one of the claims 1 to2, wherein n=1, R² and R⁴ are independently the residue of cyclic oracyclic terpene or the residue of a terpenoic aldehyde having 4 to 15carbon atoms and R³ and R⁵ are H.
 5. Use of a compound of formula Iaccording to one of the claims 1 to 2, wherein n=1, R² and R⁴ areindependently cycloalkyl, cycloalkenyl residues having 4 to 15 carbonatoms, and R³ and R⁵ are H.
 6. Use of a compound of formula I accordingto one of the claims 1 to 2, wherein n=1, R² and R⁴ are independentlyaromatic residues having 4 to 15 carbon atoms, and R³ and R⁵ are H. 7.Use of a compound of formula I according to one of the claims 1 to 2,wherein n=1, R² and R³ are alkyl, alkenyl, alkynyl residues havingtogether 5 to 17 carbon atoms, and R⁴ and R⁵ are alkyl, alkenyl, alkynylresidues having together 5 to 17 carbon atoms.
 8. Use of a compound offormula I according to one of the claims 1 to 2, wherein n=1, and R²,R³, R⁴ and R⁵ are the residues of cyclic or acyclic terpene or of aterpenoic ketone having 4 to 15 carbon atoms.
 9. Use of a compound offormula I according to one of the claims 1 to 2, wherein n=1, and R²,R³, R⁴ and R⁵ are the residues of cycloaliphatic ketones having 8 to 18carbon atoms.
 10. Use of a compound of formula I according to claim 1wherein n=1, and R², R³, R⁴ and R⁵ are the residues of araliphaticketones having 8 to 18 carbon atoms.
 11. Use of a compound of formula Iaccording one of the preceding claims, wherein n=1 and R¹=H.
 12. Use ofa compound of formula I according to one of the claims 1 to 10, whereinn=1 and R¹ represents a linear or branched alkyl, alkenyl, aralkyl oraryl comprising 1 to 20 carbon atoms.
 13. Use of a compound of formula Iaccording to one of the claims 1 to 11, wherein n=1, R¹=H, A is anaromatic ring; or A is an aromatic ring substituted with one or moreresidues selected from the group of alkyl, alkenyl, alkynyl, and alkoxy;or A is an aromatic ring bearing a residue that together with the carbonatoms to which it is attached forms an aromatic or alicyclic ring, or anaromatic or alicyclic ring bearing one or more heteroatoms selected fromoxygen, nitrogen or sulphur, which aromatic or alicyclic ring may besubstituted with one or more residues selected from the group of alkyl,alkenyl, and alkynyl residues.
 14. Use of a compound of formula Iaccording to one of the claims 1 and 3 to 11, wherein n=1, R¹=H, and Ais a heteroaromatic; or A is an aromatic or heteroaromatic ringsubstituted with one or more residues selected from the group —OH,—O-alkyl, -alkoxyalkoxy, —O-aralkyl, —O-aryl, —O-acyl, —NO₂, —NH₂,—NH-alkyl, —N(alkyl)₂, —NH-acyl, —N(acyl)₂, —SH, —S-alkyl, —S-aryl; or Ais an aromatic or heteroaromatic ring bearing a residue that togetherwith the carbon atoms to which it is attached forms an aromatic oralicyclic ring, or an aromatic or alicyclic ring bearing one or moreheteroatoms selected from oxygen, nitrogen or sulphur, which aromatic oralicyclic ring may be substituted with one or more residues selectedfrom the group of alkyl, alkenyl, and alkynyl residues.
 15. Use of acompound of formula I according to any one of the preceding claims,wherein R² and R⁴ are the same, and R³ and R⁵ are the same.
 16. Aconsumer product comprising a compound of formula I according to one ofthe claims 1 to
 15. 17. A consumer product according to claim 16 whereinthe product is a fine fragrance, home care product, or personal careproduct.
 18. A compound of formula I

wherein n is 1, R¹ is H, methyl, phenyl, A is phenyl,6-tert-butyl-1,1-dimethyl-indan-4-yl, 2,4-dimethylphenyl,3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,5,6,7,8-tetrahydro-2-naphthalenyl, 1,1,2,3,3-pentamethyl-indan-5-yl,2-naphthalenyl, 1,1,2,3,3,6-hexamethyl-indan-5-yl,1,1,2,6-tetra-methyl-3-(1-methylethyl)-indan-5-yl,3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,3-ethyl-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl,4-alkoxy-phenyl, 4-dialkylamino-phenyl, 4-acylamino-phenyl,4-diacylamino-phenyl, 3,4-(methylenedioxy)-phenyl, 3,4-dialkoxy-phenyl,4-(2-methoxyethoxy)-phenyl, 3,4-di-(2-methoxyethoxy)-phenyl,4-[2-(2-methoxyethoxy)-ethoxy]-phenyl,3,4-di-[2-(2-methoxyethoxy)-ethoxy]-phenyl,2,3-dihydro-benzo[1,4]dioxin-6-yl, R² and R⁴ are hydrogen, and R³═R⁵ are6,10-dimethylundec-9-ene-2-yl, 2,4-dimethyl-cyclohex-3-ene-1-yl,1,3,5-trimethyl-cyclohex-1-ene-4-yl,4-(4-hydroxy-4-methyl-pentyl)-cyclohex-3-ene-1-yl, pent-1-enyl, hexyl,6-methyl-hept-5-ene-2-yl, nonyl, 2-decyl, 9-decenyl, decyl, undecyl,2-undecyl, heptyl, octyl, 8-decenyl, 1-phenyl-ethyl,(4-methyl-phenyl)-methyl, 2,6-dimethyl-heptyl,2,6,10-trimethyl-undeca-5,9-dienyl, 2,6-dimethyl-6-hydroxy-heptyl,2-(3-isopropyl-phenyl)-propyl,4-(4-methyl-pent-3-enyl)-cyclohex-3-ene-1-yl,4-(2,6,6-trimethylcyclohex-2-en-1-yl)-2-butyl,3-(4-tert-butylphenyl)-2-propyl, 2-(4-tert-butylphenyl)-ethyl,3-(benzo[1,3]dioxol-5-yl)-2-propyl, 2,6-dimethyl-5-heptenyl,3-(p-isopropyl-phenyl)-2-propyl, (3,7-dimethyl-oct6-enyloxy)-methyl,(5Z)-octa-1,5-dienyl, 1-nonenyl, 1-undecenyl,2,6-dimethyl-hepta-1,5-dienyl, 2,6-dimethyl-octa-1,5-dienyl, or R² andR⁴ are methyl, and R³═R⁵ are pentyl, hexyl, heptyl, octyl, nonyl,2-phenyl-ethyl, 4-methyl-pent-3-ene-1-yl,4,8-dimethyl-nona-3,7-dien-1-yl,(2,6,6-trimethylcyclohex-1-ene-1-yl)-ethyl, (2,6,6-trimethylcyclohex-1-ene-2-yl)-ethyl, 2-(4-hydroxyphenyl)-ethyl,(1,3-benzodioxole-5-yl)-ethyl, or R² and R⁴ are ethyl, and R³═R⁵ are5-methyl-hex-4-en-2-yl, or R²CHR³═R⁴CHR⁵ are 2-heptyl-cyclopentyl,7-methyl-3,4-dihydro-2H-1,5-benzodioxepin-3-yl,3-methyl-cyclopentadecyl, cyclopentadecyl, 5-cyclohexadecen-1-yl,4-(1,1-dimethylpropyl)-cyclohexyl,2-(2-methylethyl)-5-methyl-cyclohexyl,2-(1-methylethyl)-5-methyl-cyclohexyl, 2-(butan-2-yl)-cyclohexyl,3-(2-oxo-propyl)-2-pentyl-cyclopentyl,2-pentyl-3-(methoxycarbonylmethyl)-cyclopentyl.
 19. Compounds of formulaI according to claim 18 wherein R¹ is H.